Concentric coil tubing, also commonly referred to as “endless tubing”, is widely used in the oil and gas service industries for conducting many different stimulation and or work-overs of newly drilled and older producing wells. Coil tubing generally comprises a continuously “spooled” indefinite length of tubing, usually constructed of steel although other materials have been used.
Oil/gas service tools are commonly connected to a coiled tubing unit and inserted into wellbores for downhole cleaning or formation stimulation. Examples of such tools include wash nozzles and jetting nozzles. For example, a wash nozzle connected to the end of coiled tubing is inserted into a wellbore after which, a pressurized cleaning fluid exemplified by water, acids or nitrogen, and the like, is pumped into the coil tubing and exits through the wash nozzle in the vicinity of the area to be cleaned. Such wash nozzles are commonly used to remove sand plugs, wax, calcium or debris such as failed linings from within the coiled tubing unit. Accumulations of sand plugs and/or wax and/or calcium, and/or debris significantly reduce the well performance. Similarly, wash nozzles can be used to clean other confined and/or tubular spaces exemplified by sewer lines, industrial waste lines, and the like.
Existing jetting tools may have static or moveable jetting nozzles. The first are more simple but its performance is limited to the areas of the conduit where the nozzle jet is directed, while the moveable nozzles have the advantage of sweeping the circumference of the tool but have a lower reliability due to the failure in moveable parts in contact with the well fluids and solids or even conduit surface, and the difficulties in the control of the nozzles spinning which causes the loss of energy of the jet. Some other jetting tools use alternatives to address these difficulties but result in a higher risk to the formation.
An emerging jetting nozzle technology called Vortex Generating Washer Nozzles (PCT/CA2016/050751) uses an innovative system consisting on static nozzles which generate spiral currents thanks to a high-speed pulsatile and intermittent fluid flow covering a 360 degrees sweep of the circumference of the conduit.
Downhole jet pumping is a common oil/gas process used to extract fluids inside the wellbore up to the surface, by means of the injection of a pressurized external fluid which passes through a venturi nozzle, creating a pressure drop at the venturi throat which sucks the wellbore fluids and to later pump them up to the surface.
Existing coiled tubing servicing tools in the oil/gas have tested the effectiveness of the methods separately, by means of specialized tools for specific conditions of the wells or ducts, but with a lack of flexibility to be used in different well conditions, and with a poor integration between the two operating principles, making necessary having several specialized tools to satisfy the demand for services in fields having wells with different conditions, from depth and wellbore fluid pressure to different density and viscosity fluids.